give (someone) a piece of (one's) mind
To tell someone how one feels, often while expressing anger or frustration. I had to give Sarah a piece of my mind after she left my car a mess for the third time this week. Boy, the boss really gave me a piece of his mind after that awful meeting.
give somebody a piece of your ˈmind
(informal) angrily tell somebody your true opinion of them; criticize somebody angrily: If he doesn’t turn that music down soon, I’m going to give him a piece of my mind. OPPOSITE: bite your tongue